Events and Listeners: Decoupling Application Logic

As applications grow, placing all logic in controllers becomes messy. Events help separate concerns.

  Example:
  When a user registers:
  - Send welcome email
  - Create profile
  - Notify admin
  
  All without cluttering the controller.
  
  ## Create event and listener
  
  ```bash
  php artisan make:event UserRegistered
  php artisan make:listener SendWelcomeEmail --event=UserRegistered
  ```
  
  ## Fire event
  
  ```php
  event(new UserRegistered($user));
  ```
  
  ## Listener handle
  
  ```php
  public function handle(UserRegistered $event) {
    Mail::to($event->user->email)->send(new WelcomeMail());
  }
  ```
  
  ## Event flow
  
  ```mermaid
  flowchart TD
    A[Action Occurs] --> B[Event Fired]
    B --> C[Listener 1]
    B --> D[Listener 2]
    B --> E[Listener 3]
  ```
  
  Events make large systems easier to extend.
  
  In the next tutorial, we will move heavy work into background queues.